The present disclosure relates to electric machines, and more particularly but not exclusively to electrically excite synchronous machines (EESMs) and the control thereof during power supply failure. EESM control remains an area of significant interest. Existing control proposals suffer from a number of shortcomings, drawbacks and disadvantages. For example, in the instance of power supply failure, supplemental energy storage may be necessary to maintain control of EESMs. Undesirable system operating conditions may also occur including, for example, drive trip events. Existing controls lack flexibility and robustness when faced with a multiplicity of power supply failure conditions. There remains a significant need for the unique apparatuses, methods, systems and techniques disclosed herein.